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Nutrition support for endurance athletes

Endurance sport rewards athletes who fuel the work. We help runners, triathletes, cyclists, swimmers, rowers and skiers match intake to training, build race plans and protect long-term health, through online consultations.

At a glance

  • Main fuel: Carbohydrate, periodised to training
  • Training volume: High, often daily or twice daily
  • Race-day focus: Pre-event loading and in-event carbohydrate
  • Health watch: Low energy availability (RED-S)


What endurance sports share, and where they differ

What endurance sports share is volume. Athletes accumulate many hours of training each week, so daily energy and carbohydrate needs are high and shift with the training cycle. Glycogen availability limits performance in longer events, and fuelling during exercise becomes a skill in its own right. Endurance sport is also one of the settings the IOC identifies as carrying a higher risk of low energy availability and RED-S.

The differences matter just as much. Runners contend with impact and a jolted gut, cyclists can eat easily on the bike, swimmers have almost no chance to eat mid-session, and rowers combine endurance with power and, for lightweights, a weight limit. Triathletes and duathletes juggle several disciplines, while cross-country skiers race in the cold, where appetite, fluid and kit all complicate fuelling.

Event length shapes the plan. Short, intense races need good daily fuelling and a well-timed pre-race meal; events lasting more than 90 minutes benefit from carbohydrate loading; and events lasting several hours need a rehearsed hourly plan for carbohydrate, fluid and sodium. We start from your sport, your events and your training week, then build support that fits.


Nutrition priorities for endurance athletes


Periodise carbohydrate

Endurance training of 1–3 h a day typically calls for 6–10 g/kg/day of carbohydrate, rising to 8–12 g/kg/day for more than 4–5 h a day; easier days need less. [1]


Load for longer events

For events lasting more than 90 min, 10–12 g/kg/day of carbohydrate for 36–48 h beforehand helps maximise glycogen stores. [1]


Fuel during exercise

Guidance ranges from 30–60 g/h for 1–2.5 h up to 90 g/h beyond 2.5–3 h, using glucose–fructose mixes. Gut tolerance is trainable. [1]


Spread protein through the day

Most endurance athletes do well on 1.4–2.0 g/kg/day, in servings of about 20–40 g every 3–4 h, to support adaptation and recovery. [2]


Personalise hydration

Aim to avoid losing more than 2% of body mass through sweat, with fluid and sodium tailored to your sport, sweat rate and conditions. [1]


Screen for RED-S

Low energy availability affects hormones, bone, immunity and performance. Our RED-S specialists screen for warning signs and work with medical teams where needed. [4]


Endurance event-day structure

  1. Days before: Match carbohydrate to event length: a carbohydrate-focused day for shorter races, or 10–12 g/kg/day over 36–48 h for events lasting more than 90 min. [1]
  2. Pre-event meal: Eat 1–4 g/kg of carbohydrate 1–4 h before events lasting more than 60 min, using foods and timings rehearsed in training. [1]
  3. During the event: Small amounts of carbohydrate or a mouth rinse can help in events of 45–75 min; longer events need regular carbohydrate and fluid to a practised hourly plan. [1]
  4. After the event: If competing again soon, 1.0–1.2 g/kg/h of carbohydrate for the first 4 h restores glycogen fastest, alongside about 0.3 g/kg protein. [1]

General guidance from sports nutrition consensus statements. Your practitioner will tailor amounts to you.


Endurance sports we support


Road running and marathon

Daily carbohydrate matched to mileage, marathon loading, gut training and bone health.


Trail and ultra running

Eating on the move for many hours, mixing real food with sports products, and managing appetite late in races.


Triathlon and Ironman

Double-session days, recovery between disciplines and a bike-leg fuelling plan that protects the run.


Duathlon

Run–bike–run racing where most fuel goes in on the bike to protect the second run.


Road, track and mountain biking

High hourly carbohydrate on the bike, power support for track sprinters and attention to bone health.


Swimming and open-water swimming

Fuelling around early sessions, heats and finals, and practised feeds at set points in open water.


Rowing

Very high energy needs, recovery between outings and safe, supervised approaches for lightweight rowers.


Cross-country skiing

Fuelling in the cold, recovering between races at championships and keeping drinks usable in freezing conditions.


What we help with

  • Under-fuelling during high-volume training blocks
  • Gut problems in races and long sessions
  • Running out of energy late in events
  • Recurring injury, illness or persistent fatigue
  • Pressure around body weight and race weight
  • Fitting fuelling around work and early starts


Ongoing support, not one-off sessions

We do not work with athletes on a one-off basis. Sports nutrition works best when it adapts to your training, so we recommend an initial consultation followed by at least three follow-ups.


Sports in this group


Who you could work with


Book your consultation

Book an initial consultation or book a free discovery call to talk it through first. All consultations are online.


Explore more

See all the sports we work with, our RED-S nutrition support, or meet the team.


Frequently asked questions


Which endurance sports do you support?

We support road, trail and ultra runners, triathletes and duathletes, road, track and mountain bike cyclists, pool and open-water swimmers, rowers and cross-country skiers. Each sport has its own fuelling challenges, so support is built around your discipline, events and training week. All consultations are online.


What is RED-S and why does it matter for endurance athletes?

Relative Energy Deficiency in Sport happens when energy intake does not cover the demands of training and the body's everyday functions. It can affect hormones, bone, immunity, mood and performance, and the IOC recognises endurance athletes as a higher-risk group. Our RED-S specialists assess and support athletes, working alongside medical teams where needed.


Do endurance athletes need supplements?

Most needs can be met with food. A few supplements, such as caffeine at 3–6 mg/kg about 60 min before exercise, have good evidence in specific contexts, but every supplement carries contamination and anti-doping risk. We advise only where appropriate and recommend batch-tested products such as Informed Sport.


What experience does your team have in sport?

Our team has supported Olympic and Olympic-pathway athletes, and Jenaed is Lead Sports Dietitian at Imperial College London and Cambridge University. Whatever your level, we build support around your training and goals.


How does ongoing support work?

We do not work with athletes on a one-off basis. Endurance fuelling changes through base training, race-specific blocks and the taper, so we recommend a minimum of three follow-up consultations after your initial consultation, timed around your key training phases and events.


Do you support young endurance athletes?

This page is for adult athletes. Young endurance athletes are supported through our paediatric team.


References

  1. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016;116(3):501–528.
  2. Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
  3. Maughan RJ, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.
  4. Mountjoy M, et al. 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097.
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